


The Impossible Bond

by pherryt



Series: SPN ABO Bingo [4]
Category: Supernatural
Genre: ABO, Alpha!Jimmy, Alternate Universe - High School, Claiming, Knotting, M/M, Mating, Polyamory, Rut, Top!Cas, Top!Jimmy, Triad - Freeform, Twincest, alpha!cas, bottom!Dean, bottom!jimmy, heat - Freeform, omega!dean, presenting, switch!cas, switch!jimmy
Language: English
Status: Completed
Published: 2017-08-01
Updated: 2017-08-01
Packaged: 2018-12-09 16:28:13
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 4,358
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/11672829
Author URL: https://archiveofourown.org/users/pherryt/pseuds/pherryt
Summary: Friends for years, Dean, Cas and Jimmy were inseparable but everyone around them knew it wouldn't last once they'd presented.





	1. Implementing the Plan - Step 1

**Author's Note:**

> This chapter is for the Mating/Claiming square on my Bingo Sheet

Two Alphas shouldn’t be able to claim each other. It certainly had _never_ happened in anyone’s memory before. The fact that Cas and Jimmy were brothers was actually less of a problem than the fact that they were both Alphas. Claiming someone for your mate wouldn’t work, the bonds simply would not form, if you weren’t compatible. Thousands of years’ worth of records and decades of science backed this up.

 Therefore, being brothers wasn’t an issue, though it was still looked down on by many.

The problem was that as twins, they were most likely to both present the same when the time came. They knew, before they even presented, before they knew _how_ they would present, that it might not go the way they hoped.

They’d spent _years_ looking up anything they could on same secondary gender matings and bond forming. There simply wasn’t any information to be found. They talked over their fears and plans with their best friend Dean. They concocted scenarios of all kinds – just in case.

And now the time was upon them.

Their ruts had started late at night the day after their 18th birthday, waking them from a dead sleep. Jimmy crawled into Cas’s bed, the two never more grateful than that moment that they still shared a room. That financially, their parents had never been able to separate them. The house too small, the number of children too many. The frictions between them were all too difficult to risk breaking up the only sets that got along.

Then again, their parents – like the rest of the world – could never imagine what Cas and Jimmy were about to try.

“Cas,” Jimmy groaned, sliding up against his twin, already naked and sweating and _oh so hard_.

“You ready for this Jimmy?” Cas buried his nose in the crook of Jimmy’s neck and sniffed before licking. Jimmy’s hands had migrated down to Cas’s boxers, latching onto the waistband and yanking them down. His hips twitched, and their hard cocks ground against each other. Jimmy whimpered and Cas growled.

“ _God,_ yes, knew this was coming soon, Cas, been prepping myself for you every night…need you…”

Cas’s breath hitched and he dragged his brother against his hot flesh, Jimmy clutching at whatever he could reach. Cas’s hands slid down Jimmy’s body, down his sides and over his thick thighs, sliding around to the fleshy globes of his ass.

The brothers were both panting hard when Cas dipped a single finger teasingly into Jimmy’s hole – his incredibly open and slick hole. Cas groaned, thrusting his finger further in, Jimmy crying out. Cas’s finger slid in so easily he was shocked.

“ _Every_ night, brother?”

“Yeah…” Jimmy gasped, rocking back on Cas’s finger. “I open myself up in the shower, thinking of you the whole time – how you’ll be the first to fill me. How you’ll _feeeeel….”_

“How many fingers, Jimmy?” Cas growled against his skin, mouthing at the right side of Jimmy’s throat, feeling the quickened pulse under his lips. He thrust a second finger inside just as easily as the first, Jimmy’s hole loose enough to take it. An image of Jimmy doing this to himself in the shower flashed through Cas’s mind and he groaned. “How…how many?”

“Four – _oh my god_ – I’ve…I’ve managed to work up to f-four before I -I-I… _oh god…_ Cassie…” Jimmy stuttered as two fingers turned to three. His hips pushed relentlessly, desperately against his twins.

“Before what, Jimmy?” Cas nipped lightly, a tease of the real thing.

“Before I c-c-come – oh, _please,_ Cas! I’m ready, I need you!”

“I haven’t yet reached four, Jimmy. Don’t you think we’ll need it for when my knot locks inside you? Do you think you can take it? Take my knot?” Cas rumbled against Jimmy’s throat.

Jimmy whimpered and Cas thrust a fourth finger inside, Jimmy driving down on them, head thrown back, his throat exposed even further and _oh so tempting_. Keening, he called out Cas’s name again and again. Cas couldn’t hold back any longer – he’d been dreaming of this moment for years and now he had it, he had Jimmy begging for him.

He pulled his fingers out and Jimmy whimpered. Cas pushed him down on his stomach and lifted him to his knees, blanketing Jimmy’s body with his own. Placing his mouth against Jimmy’s ear, Cas whispered, “Ready?”

“Yes, yes, yes, yes…been ready for you forever, Cas. Just do iiiit…… _ooooooh_ …” Jimmy trailed off as his brother lined up and thrust inside. Cas’s eyes closed in bliss, stilling for a brief moment, waiting, relishing in the hot, tight clench of Jimmy’s ass.

Then Jimmy shoved back and it was on. They were lost quickly to the slick movement, the frantic thrusts, the moans and the gasping of names. As they neared the end, Cas pulled out and flipped Jimmy to his back. They had to do this right.  Jimmy quickly grabbed his legs and folded them up and out, exposing his already puffy hole. He looked up at Cas with lust filled eyes, biting at his lips, skin flushed. He was a beautiful sight and Cas slid back in with a happy moan.

He hooked his arms around Jimmy’s legs and Jimmy let go to take himself in hand, Cas reaching around to massage Jimmy’s neglected knot as his own grew with every thrust.

At the pinnacle of their pleasure, when Cas abruptly locked in place inside Jimmy, he surged forward and bit his brothers neck, claiming Jimmy as his mate. Jimmy reached for Cas to do the same simultaneously and the bond formed instantly, blooming in their minds. As the bond clicked in place, they exploded as one, overwhelmed by the desire and emotions, now doubled and flooding through them.

They collapsed against each other, spent, chests heaving, locked together, their bodies still jerking with the aftershocks, come coating their bodies. Jimmy still spurted thick ropes with every hot pulse of Cas inside him.

Exchanging lazy kisses, the twins basked in the lull of their rut, their fingers playing with their matching bites.

“It worked,” Jimmy said giddily. “Holy fuck, Cas, it worked!”

“I told you it would. Didn’t you believe me?”

“I wanted to, but no one’s ever done this before. You gotta admit, the odds were not good,” Jimmy pointed out. He hummed and arched slightly as Cas’s hips twitched again.

“When’s the last time anyone tried? It is harder to prove a thing doesn’t exist, that something cannot be done than it is to prove it does or that it can. And just think…” Cas nipped at Jimmy’s ear, “This is just the first part of our impossible plan. It’s going to work, Jimmy, we’ve almost done it.” It was Cas’s turn to laugh giddily.

“Are you waxing philosophical in the middle of our _rut?_ Shouldn’t we both be mindless right about now?” Jimmy asked disbelievingly, a smile twitching at the corners of his mouth. He knew what Cas was thinking of. Jimmy couldn’t wait to implement the second part of their plan. But for now…

“A brief respite. And as soon as my knot goes down, it’s my turn…” Cas whispered in Jimmy’s ear. Jimmy shuddered at the thought, just imagining sinking into Cas for the first time, how it would _feel_.

“Oh god…” he whimpered. He already couldn’t wait.


	2. Next Step - Convince Mary

**Summary for the Chapter:**

> Cas and Jimmy succeeded where society thought 2 Alphas could not. But they weren't done yet - if they could only convince Mary of the truth.

**Notes for the Chapter:**

> written separately as a continuation - this fills the Presenting square for my SPN ABO Bingo sheet. 
> 
> There will be at least one more for this but i don't know what it is yet. Currently, thats all i've written and my bingo sheet looks like a checkerboard - oops!

Everyone expected Dean to be an Omega, and Jimmy and Cas would be Alphas, so when the twins and their best friend came of age, their parents started preparing them for what that would mean. Including the fact that the twins might come to blows over their best friend.

After all, it was literally unheard of for Alphas to mate each other, even if they _weren’t_ related, and the number of relationships between Alphas and Omegas that had multiple partners were extremely rare.

Everyone said that Dean would need to choose one of them or Cas and Jimmy would have to fight it out. Anytime he tried to protest, he was drowned out by the people in his life who all ‘knew better’ and just wanted to make sure he didn’t get hurt.

This meant that the day Dean presented as expected was both the best and the worst one in his life. He loved Jimmy and Cas equally and he didn’t want to choose and he didn’t want them to fight over him either. Alphas had been _killed_ that way. Dean didn’t want that to happen to Cas and Jimmy.

And if everything went according to the plan, it wouldn’t. Dean and the twins had been discussing their options for years, refining things as the time grew closer. But today was a school day and he’d woken up feverish, he’d woken up sweating.

He’d woken up _slick_.

And he hadn’t seen the twins in days.

Mary came to get him when he didn’t get up for school. She found him with one hand down the front of his boxers, rutting mindlessly. He opened his eyes on a sharp gasp and found her there. “Mom!” he cried out, mortified, yanking his hand out of his boxers and attempting to drag a blanket over his body even though he was too hot for that.

“Oh, sweetie…there’s nothing to be embarrassed by. I’ll call the school and let them know you won’t be coming in and I’ll bring you back a few bottles of water. It’s important to stay hydrated.” Mary left and Dean collapsed into the bed. The blanket was sweltering and his skin itched, his limbs moving restlessly. Slick gushed from his twitching hole and that was probably the strangest sensation he’d ever felt. God, it was driving him fucking crazy!

He shoved the blanket off of him again. It was too much. Too, too much. He rolled to his side, a wave of heat washing through him, over him, as he groped for the bedside table, looking for his phone. The twins, he had to call the twins. They’d made a plan. He had to let them know it was time.

His groping knocked the phone off the table and he whimpered. He rolled over further, and the friction on his dick felt both wonderful and agonizing at the same time. Phone forgotten, he rutted against the bed, swearing at the oversensitive feeling but feeling too good to stop. He imagined the twins there with him, covering him, laying him out with kisses, caressing him. He whimpered and came in his boxers, collapsing against the bed panting.

It was a relief to come and yet not enough. He groaned. He knew what he needed. With a huff he hauled himself over to the side of the of the bed and half hung off it, blearily looking for his phone. Only the mantra of “if I can call the twins, they’d be here for me” keeping him focused long enough that his fingers finally closed around it.

He pulled himself back up over the edge of the bed, and raised the phone to his eyes, thanking god it still had a charge.

Not much of one though.

He hurried to get his fingers moving, sending a single text to his would-be mates. “It’s time.”

His mom returned then, her hands carrying 6 bottles of water. “How are you holding up, sweetie?”

He groaned in response, covering his red face with his hands. “Mom, please, leave. I don’t want you seeing me like this.”

“I’ll leave in a second, Dean. Listen, it’s always been clear to everyone around you that once you went into heat, you’d be with one of the twins.  Now’s not the time. It’s too soon, and you shouldn’t make decisions like this during your heat, but I have to ask, have you been able to pick one yet?” she approached the bed, her tone curious, calm. It infuriated Dean.

“But what if I want _both_ of them?” Dean cried out from his bed as a fresh wave of heat rushed through him. “Why do you keep insisting I have to choose? _It’s not fair_!”

“Sshhh, Dean,” Mary soothed, setting down bottles of water on the table. “After this is over and you’re thinking clearly – “

“Noooooo,” Dean groaned. “It’s not my heat talkin’, mom. I’ve always wanted them both, but none of you will _listen_ to me!” Dean was sweating and already so fucking hard again. He couldn’t believe how fast that had happened. He rubbed uncomfortably against his boxers and he just wanted to get out of his clothes so badly, if only his mother would just _leave_ already. He sobbed with need, sobbed with despair, it didn’t matter which. He could no longer hold back the tears. “Why haven’t they come yet? They promised!”

“Dean, it’s impossible. You can’t –“

A door slammed below them and Mary jumped up, whirling about. Voices, loud ones, echoed through the house, the words indiscernible. Then pounding footsteps coming up the stairs, down the hall. Dean’s door slammed open, and Jimmy and Cas burst through, their clothes in disarray, both Alphas panting, their skin flushed and eyes bright and wild.

They noticed his tears, his sobs immediately.

“Dean! Are you all right?” Jimmy surged forward to go to him but Mary stood to bar their way.

“Mrs. Winchester, I don’t mean to be rude, but please, move away from our mate,” Castiel growled.

Mary stood her ground, glaring at the twins. “Dean’s presenting. He’s in heat and he’s not rational right now. I’m not allowing the three of you to make life changing decisions while he’s like this.”

“Mary,” Jimmy said, trying to pull his patience together, slowly parsing his words. “We thought of that already. The three of us discussed this before any of us presented. Dean’s our mate, and we’re his.”

“No, but that’s impossible…” she trailed off when the twins pulled their shirt collars down, exposing extremely fresh mating bites on the right side of their necks. That’s when she realized she could still smell rut coming off the Alphas.

“Jimmy and I have already claimed each other. Now it’s Dean’s turn to claim us and be claimed.” A whine rose from Dean’s throat at Cas’s words, desperation and need clear, making the Alphas’ strain to move forward, held back only by Mary and their respect for her.

“But…Alphas _can’t_ claim each other,” she protested. “And…three-way bonds are…It won’t work…” her voice wobbled uncertainly. “Will it?”

“Mary, it’s already been decided. Dean chose this. _We_ chose this, _together_ ,” Jimmy’s eyes darted behind her at another whine from Dean. “Please, let us go to him.”

Mary stared at the twins. She’d known them nearly as long as Dean had been alive. They’d always been good kids. They’d never lied to her, they’d never snuck around behind her back. But they were Alphas now, and Alphas were notorious for not being able to control themselves when in Rut, much less around an Omega in Heat. How could she know if they were telling the truth? Looking into their eyes, it _felt_ like the truth, but as a mother, she couldn’t just go on instinct – could she?

She wavered.

“Mom,” Dean panted out, “Told ya…already…waiting for them. They promised…Please…Don’t believe me, ask…ask Sam…”

Dean’s words finally registered. He _had_ already told her, explained that he’d already given his consent, pre-Heat. He wasn’t being controlled by it. She looked at them all uncertainly, biting her lip, “But…it can’t work, it can’t possibly work…”

“Mary,” Cas spoke gently, though it was apparent that it was an effort. “If it doesn’t work, what’s the worst that could happen right now? We get Dean through his first heat more comfortably and possibly walk away with broken hearts. If we don’t try, we still walk away with broken hearts. And if we do try, and it does work…the three of us get what we’ve always wanted – each other.”

“Please,” Dean whispered. “Please, mom, I love them both and I need them so bad. I can’t choose, don’t make me choose.” Dean sniffed, the devastation at the mere thought of it wafted through the room, strong enough to cover both the smell of Heat and Rut.

It hurt her heart to smell it, to know she was part of the reason her son felt so badly. It was strong. This was no mere passing fancy, and if she’d been paying any attention at all, she’d have known that long ago.

Finally, Mary relented and stepped aside.

The Alpha’s darted past her and to Dean’s side in an instant, the smell of devastation quickly replaced by arousal and joy.

Mary left quickly, shutting the door behind her and preparing to keep the family out of the house for the next 24 hours. None of them would want to be around for this.

Shaking her head on her way to get Sam, she wondered what John would say about all of this.


	3. The Final Step

**Summary for the Chapter:**

> Despite being certain they had to try, all three of them were afraid this final step wouldn't work.

**Notes for the Chapter:**

> No special square for this - this chapter simply fills the DCJ ship square :D
> 
> I'm gonna call this set done. I have a TON more squares to work on and SEVERAL different ships! wish me luck!

Only a little over an hour later, the blankets and pillows had been yanked off Dean’s too small bed and formed into a nest on the floor. The twins had Dean sandwiched between them as the three of them lay on their sides, their Omega tracing the bite he’d left on Cas’s neck with wonder.

“Is this real?” He whispered. The scent of the twins lingering rut was an underscore for the prevailing strength of Dean’s heat, temporarily lulled. The smell of his heat, of Dean’s slick and their release, drowned out all other scents. But Cas could _feel_ what Dean felt through the bond, the pure love and elation washing through him, causing him to pulse, to pump more hot come into Dean’s willing body.

Dean shuddered and closed his eyes at the feel of it, his hips grinding down lazily, his heat momentarily sated. Jimmy pressed kisses against his back and Castiel could feel that too. Feel his brothers love and longing through the bond.

Castiel leaned forward the scant inches that separated him from Dean and pressed his chapped lips against Dean’s soft ones. Their lips parted on a gasp, all this still so new to them, and he met Dean’s tongue with his own for several long, deep kisses. He finally pulled away, cupping Dean’s cheek in his hand, and nodded.

“Yes, it’s very real and…” Cas’s dick let out one last spurt and his knot slipped free. Dean whimpered when Cas pulled out. “And it’s Jimmy’s turn to receive your mark. And for you to receive his.” He dropped one last kiss to Deans lips and helped turn the eager Omega over, the heat returning now that he was empty.

Dean stared into Jimmy’s blue eyes – so similar and yet so different than Cas’s, he could never understand how people could confuse the two Alphas. Jimmy reached out tentatively to caress Dean’s face.

“Okay, Dean, this is the tricky part. We already both wear my brothers mark…we won’t be able to do this simultaneously without risk to one of them,” Jimmy said nervously, worried that this wouldn’t work, after all they’d accomplished so far.

“No, Jimmy, there’s a way.” Dean reached Jimmy’s hand, pulling it off his face, and sliding it over to rest over Cas’s claiming bite. The meaning was implicit and Jimmy frowned.

“No, but, if I do that, it’ll break the bond between you and Cas!” Jimmy protested. Cas’s arm, wrapped around Dean’s waist, tightened and Dean could feel the fear of such a thing pulse through that bond from Cas.

“Nuh uh. I found…” Dean’s heat started ramping up again, making thinking and talking more difficult. “f-found an article about…t-the a-acident-tal Triad b-back in the – “ he whined, his body moving of its own volition against Jimmy’s, already seeking out his knot. From what he’d read about heats, there should be longer lulls between the need for knotting, but he was already burning up. “-d-during the gold rush. D-don’t you rem-remember? T-thought I s-s-s-showed you that…”

Something prodded through his slick and into his hole and Dean dropped his head back on Cas’s shoulder with a sigh of relief. It wasn’t a knot, but having something _– anything_ – filling him, quelled the heat enough to let him think, to talk. With Cas’s fingers inside him, lazily stroking, Dean tightened his grip on Jimmy’s wrist. “It won’t obliterate the bond, Jimmy, I’m positive. I studied that article. I compared it to other failed Triads. I compared it to the few successful ones I could find. All of them have one thing in common – if the Alpha’s claimed each other first and _then_ their Omega, the bond won’t short circuit. It won’t pull a stronger claim – one over the other- because they’re already one. It’s why too many of them fail. The Alpha’s have to bond first, like you and Cas did.”

“But…Alpha’s don’t bond. Everyone knows that…” Jimmy whispered.

“Except they do. They can. We’re proof enough of that. I think Dean’s right. This must be the reason why there are so few Triads. Since no one believes Alpha’s can do what we have done, they don’t take the right steps. And if the Triads discuss what those right steps are, no one believes them.” Cas trailed off and Dean could feel the excitement, the renewed hope coming off him, echoed in Jimmy’s eyes.

“C’mon, Alpha…” Dean smirked at Jimmy, “Let’s finish this and prove them _all_ wrong.”

With a needy growl, Jimmy launched forward and covered Dean’s mouth with his. Dean’s eyes rolled back at the sudden, oh so welcome attack. Whimpered when Cas’s fingers withdrew, leaving him empty and wanting once more. Jimmy rolled to his back in the nest, hands roaming over Dean’s sweat slicked body, coming to rest on his ass. Jimmy palmed the globes under his hands, kneaded them, pulled them apart, heard Cas gasp at the sight and Jimmy smirked.

Without warning, his heat overtaking him, need pulling at him, Dean pulled back, breaking the kiss. He pushed his hands against Jimmy’s chest and scooted lower, sliding down his body before sitting up. Dean smirked down at Jimmy, grabbed at the hard length prodding his ass, lined it up and sank down on Jimmy’s cock.

Jimmy shouted and arched up in his surprise, driving himself deeper inside of Dean. Dean groaned at how full he felt, how _good_ he felt. They were locked in place for a bare moment before the heat took over once more and Dean and Jimmy frantically moved against each other. Jimmy thrusting up, up, up into Dean’s slick, hot channel and Dean riding Jimmy’s cock, clutching at the Alpha’s shoulders and biting his lips.

Castiel groaned beside them. Watching them was torture, but _feeling_ Dean and Jimmy was even more so.  Getting up, he positioned himself behind Dean so he could run his own hands along Dean’s body, his eyes glued to where his mates – _his mates! –_ were joined together. Watching Jimmy disappear, thrusting into Dean’s ass, knowing how good it felt to both give _and_ receive – to _feel_ how both of them felt right now…

Cas had to refrain from leaning over, from mouthing at Dean’s neck, from interrupting their claiming. He backed off and sat back on his heels, taking his hard, throbbing dick into his hand. He watched them lose themselves in each other, in their pleasure, Jimmy’s knot catching on Dean’s rim. Cas’s hand sped up, imagining it was Dean or Jimmy he was thrusting into.

Dean fell forward with a cry as Jimmy locked inside him, nuzzling at Jimmy’s throat, searching for the right spot for his bite. He felt Jimmy mouthing at his neck and he clenched around Jimmy’s hard cock, around the knot. Still moving, grinding down, Dean found the spot and bit just as Jimmy did the same. Jimmy’s teeth sunk into the bite Cas had left behind and all three of them exploded at once.

If they’d thought the bond was strong before, when the circle completed, it became overwhelming. Dean collapsed on Jimmy, panting, hips moving, lost in sensation as Jimmy chased his release. When Dean finally came to himself, he realized that not only was his front coated in his own come – not once, but twice – but his back was also covered. Looking over his shoulder at Cas, Dean smirked.

“Feel a little left out back there?”

Cas crowded closer, sliding his hands over Dean’s back, rubbing his come into the Omega’s skin. “Maybe just a little,” he conceded. With careful maneuvering, Cas helped Jimmy and Dean roll back over to their sides and heedless of the sticky come covering his back, Cas plastered himself against Dean. Their legs tangled together and their hands reached for each other, pressing as close as they could get. Dean would gasp and arch with every throbbing pulse of Jimmy inside him. Cas pressed kisses along his back while Jimmy took Dean’s lips in a gentle, soft kiss.

After long moments, a feeling pushed through the bond, rising and strengthening till the three of them were laughing giddily, unsure of who was saying what. They were all feeling it, the relief, the happiness, the pleasure – the pure love they held for each other.

“Fuck, it worked,” Dean breathed between his giggles.

“It did,” Jimmy said with awe. “Oh my _god!_ It did! What do you think of that, Cassie?”

A smug, self-satisfied feeling pulsed through the bond. Cas, ever the one of few words, taking full advantage of the bond, right from the start.

Dean smirked at Jimmy. “I think he’s saying, ‘I told you so.’”

“Yeah, seems like. Guess I’ll let it slide this time,” Jimmy said happily.

“Me too,” Dean agreed. The three of them relaxed into each other’s arms, basking blissfully in the messy tangle of limbs, the hazy scent of their lovemaking, and the warm feeling of love that washed through them like waves.

This was home, Dean thought as he dozed lightly between them. Soon his heat would return, and the urgency of it, but right now, he was content and happy and _home._


End file.
